1. Field of the Invention
The present invention relates to an ultrasonic imaging apparatus configured to scan a subject with ultrasonic waves to generate an image showing the morphology of the subject and an image showing the surface of the subject, and also relates to a method for generating an ultrasonic image.
2. Description of the Conventional Techniques
An ultrasonic imaging apparatus is capable of 3-dimensionally scanning a subject with ultrasonic waves to acquire volume data of the subject (e.g., Japanese Unexamined Patent Application Publication JP-A 2006-51360). In conventional techniques, by scanning while changing the position of an ultrasonic probe on the surface of a subject's body and coupling volume data acquired at the respective positions, volume data of a wider range is generated.
However, in the conventional techniques, even when coupling a plurality of volume data, it is difficult to grasp which site of the subject has been scanned, from the volume data. For example, in the mammary gland region, the internal structure is very similar at each site. Therefore, when reexamining the mammary gland region, it is difficult to grasp which site in the mammary gland region has been scanned, from a 3-dimensional image based on the volume data.
Further, in the acquired volume data, if a region of interest (ROI) is set to a site showing the inside of a subject's body, a region other than the ROI is eliminated and only an image of the ROI is displayed. Because the surface of the subject's body is not shown in the image, it is difficult to grasp the positional relationship between the surface of the subject's body and the ROI.
On the other hand, in the acquired volume data, if the site showing the surface of the subject's body is included in the ROI, an image showing the surface of the body is displayed. However, because the surface of the body is displayed as an image, the inside of the subject' body is not displayed in the image. Therefore, when executing an operation or puncture, it is not possible to previously display an image showing the internal structure of the subject, so that it is impossible to fully utilize information of the volume data.
As stated above, in the conventional techniques, it is difficult to grasp the positional relationship between the surface of a subject's body and a region of interest (ROI) when setting the region of interest (ROI) to a site showing the inside of the subject as well as when setting the region of interest (ROI) to the surface of the subject's body. Consequently, it is difficult to grasp which site of the subject has been scanned.